The present invention relates to a terminal board, and more particularly, to a terminal board which is suitable for use with components or the like to which a motor power source of an electric vehicle is to be connected.
As a first related-art terminal board, Japanese Patent Publication No. 11-144783A discloses a terminal board which includes a board body formed of synthetic resin and a nut embedded in the board body by insert molding, to which two terminals superposed one on another is fixed with a bolt (cf., Pages 2-3 and FIG. 1).
As a second related-art terminal board, Japanese Patent Publication No. 2001-251089A discloses a terminal board which is provided inside a shield case made of aluminum die casting for connecting a terminal of a motor cable to a motor of an electric vehicle (cf., Pages 3-4 and FIG. 1).
In the first related-art terminal board, the nut is embedded by insert molding in such a manner that an upper end face of the nut is slightly projected from the terminal board. There is such a problem that in a case where the upper end face of the nut is not projected from the terminal board, the nut will be unable to establish an electric connection with the terminals, or alternatively, in a case where the upper end face is projected too much, a bonding length between the nut and the terminal board will be short, resulting in deterioration of bonding strength. The case has been the same, not only with the nut which has been fixed to the board body by insert molding, but also with the nut which has been fixed by heat pressure fitting or pressure fitting. A height of the nut with respect to the board body must be adjusted with high precision when manufactured, and it is a problem that high production cost would be required.
As shown in FIGS. 10 and 11, in the second related-art terminal board, a terminal board 30 in which a square nut 31 is embedded is fixed to a shield case 32 and mounted to a motor case 33. A bus bar 34 which is connected to a stator terminal 42 at its one end has a connecting portion 35 fixed to the other end which is faced with the terminal board 30. On the other hand, a terminal metal 38 fixed to a motor cable 36 is inserted into an insertion hole 39 of the shield case 32 which is provided at a side area of the terminal board 30 to be superposed on the connecting portion 35 of the bus bar 34, and they are fixed to the terminal board 30 with a bolt 40 which is screwed over the square nut 31. A waterproof rubber plug 41 inserted over the motor cable 36 is tightly fitted to an inlet of the insertion hole 39 to attain waterproof performance.
In a case where the square nut 31 which has been fixed to the terminal board 30 by insert molding, heat pressure fitting, pressure fitting, etc is projected from an upper face of the terminal board 30 as shown in FIG. 12, there is such a problem that the terminal metal 38 of the motor cable 36 which has been inserted through the insertion hole 39 at the side area may interfere with a side face of the square nut 31, and may result in deterioration of assembling workability or difficulty in assembling performance.
Moreover, in a case where the terminal metal 38 of the motor cable 36 which has been inserted through the insertion hole 39 is different in height from the square nut 31, and there is a gap C between them as shown in FIG. 13. In such a condition, there is such an anxiety that, when the terminal metal 38 is fastened to the square nut 31 with the bolt 40, the motor cable 36 may be inclined downward or bent as shown in FIG. 14, so that a gap C′ will be created between the waterproof rubber plug 41 and the insertion part 39, thus badly affecting the waterproof performance. Under the circumstances, in order to prevent this phenomenon, it is necessary to manufacture the square nut 31 which has been fixed to the terminal board 30 and the insertion hole 39 with high precision so that they may have appropriate relative heights, and there is a problem that high production cost would be required.
Further, in a case where the connecting portion 35 is connected to a bus bar 51 which is provided on a connecting apparatus 50 as shown in FIG. 15, and a height H of the bus bar 51 is different from a height h of the square nut 31, there is such an anxiety that, when the bus bar 51 is fixed to the square nut 31 with the bolt 40, an undue force may be exerted on the bus bar 51 and the connecting apparatus 50 to render them distorted, so that the connecting apparatus 50 may be broken. In order to cope with these problems, it is necessary to take such countermeasures that the bus bar 51 and the terminal board 30 may be manufactured to have relative heights with high precision, or alternatively, the connecting apparatus 50 may be designed so as not to be distorted. In this case, however, not only the high production cost but also heavy weight and large outer dimension are additional problems.